1. Field of the Invention
The present invention relates to a mirror and an angle detection device. More specifically, the present invention relates to an exterior mirror for vehicles, and an angle detection device for detecting a tilted angle of a mirror surface of the exterior mirror.
2. Description of the Related Arts
There is an exterior mirror having an angle adjusting device, which adjusts tilted angle of the exterior mirror to obtain good rear side view. In such an exterior mirror, the tilted angle of the mirror surface can be adjusted to meet the viewing angle of the driver. However, since it is complicated to delicately readjust the tilted angle whenever the driver is changed, it is desired to reproduce the tilted angle suitable for respective driver.
Various suggestions have been made to detect the tilted angle for reproducing the tilted angle of the mirror surface. For example, an angle detecting device having a resistor, slidable connect which slides the resistor according to the variation (tilting) of the mirror surface has been suggested. According to this device, since the slidable connect moves to meet the tilting of the mirror surface to change the voltage, the voltage can be detected to thereby detect the tilted angle (For Example, see Japanese Patent Laid-Open No. 10-264726, hereinafter referred to as Patent Document 1). An angle detection device has also be well-known, which utilizes a magnet and Hall element to detect the tilted angle of the mirror surface depending on the strength of the magnetic force changed by tilting the mirror surface.
However, in the case of the angle detection device, for example, utilizing a slidable connect, since the resistor is worn by the sliding, the output is sometimes changed. Also, worn dusts and sliding noise will be disadvantageously generated.
In the angle detection device utilizing a magnet, due to the influence of the magnetism of the motor or such for tilting the mirror surface sometimes changes the output. Also, the position of the magnet and Hall element are restriction, sometimes making the freedom of the design narrow. Also, the use of the magnet, which is expensive, arises a problem for requiring much more cost. Also, when the slidable connect or the magnetic is used, hysteresis will be generated in the output.
An object of the present invention is, therefore, to provide a mirror and an angle detection device which can solve the problems associated with the prior arts.